Figure 1
Top: Hapmap data of LD spanning a 330 kb segment of chromosome 4q in the Yoruba (Nigerian) population (LD map drawn using MARKER (see methods)); LD between each SNP pair is colour-coded (red dots represent an absolute R2 > 0.3, green dots indicate R2 of 0.1 to 0.3, grey dots indicate R2 of 0.05 to 0.1 and absence of dots represents pairs with R2 ≤ 0.05). Middle: Genes on the segment are indicated as black boxes, the position of the 9 SNP markers as vertical lines below the boxes, with arrows indicating direction of transcription. Bottom: Haplotype structure of the genomic segment in Gambians illustrating four haplotype blocks of high within- and low between-cluster diversity and the haplotype frequencies within each block beneath. Dots and shading indicate the configuration of the protective and risk haplotypes respectively. The dark shading spanning the IL8 locus shows the configuration in blocks 3 and 4 which is shared by the risk and protective haplotypes, differing only at SNP positions 1, 2 and 3 across the AFP and AFM loci but sharing allelic configuration at sites within, and telomeric to, IL8.